I just recently set up Google Apps (Standard) on my domain, and I have a catch-all e-mail address on it that I pull e-mail from locally, so I can easily receive e-mail to anything@example.com. Now I want it to work in reverse -- I want to be able to send from any arbitrary address on my domain, by just including a From: foo@example.com header with my message. Unfortunately Gmail will rewrite the header to use whichever e-mail address I authenticated as. Since foo@example.com doesn't actually exist (the incoming e-mails to it are caught by the catch-all, so there's no need to make an actual foo account), I can't authenticate as it; I have to authenticate as my catch-all address, and then the e-mail shows up as sent from that address regardless of the From header. Gmail does support adding additional valid From addresses (in Settings -> Accounts), but I don't want to do that every time I have a new whatever@example.com I want to send from. Is there a way to tell Gmail/Google Apps "I control all e-mail from example.com, as long as the from address is on that domain just leave it alone"?

Better multiple identity and signature management. Set up multiple "identities" in Thunderbird with email address-specific signatures, which you can't do in web-based Gmail. Hit the "Manage Identities" button in your Account Preferences dialog. The various identities you choose will be available as a dropdown in the From: field in new messages, just like in web-based Gmail. You can also create and automatically attach a vCard to your outgoing messages on a per-identity basis with T-bird, and choose to compose your messages as HTML or plain text per identity, too.

About your other unintended question that I accidentally took as the actual question before:

Is there a way to tell Gmail/Google
Apps "I control all e-mail from
example.com, as long as the from
address is on that domain just leave
it alone"?

I don't think this is what I'm looking for. I only have one domain, I just want to be able to send e-mail from any account on that domain regardless of the account I authenticated as. There's no second domain I need to alias
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Michael MrozekDec 20 '10 at 15:58

Oh, my bad again @Michael! Clearly I didn't understand your question before. I'll edit the answer but I can't think of anyway to do that within google apps.
–
CawasDec 20 '10 at 16:38

@Andre true. Sometimes I'm in the wrong mood to answer questions, and I don't even smoke pot!
–
CawasMay 2 '11 at 15:53

1

You can't do this with plain Thunderbird either: you still have to create all those identities before using them. The Virtual Identity addon solves that however. Shame Gmail doesn't...
–
romkynsJul 23 '11 at 21:13